But due to the lower extraction efficiency of the SFC, on one hand, a lot of beam lost, and on other hand, outgas from the surface of the electrostatic deflector is serious because of beam hitting.

• 但由于SFC的引出效率比较低,只有30%25左右,一方面损失了大量束流,另一方面许多束流损失在引出静电偏转板上,造成了大量出气,破坏了真空,难以维持长期大束流运行。